We all know smoking is bad for your health. But so are diseases. A new study has revealed that smoking can be more harmful than HIV, which not that long ago was considered a certain death sentence. For Americans with HIV infections, smoking does more to reduce their life expectancy than the virus itself. The study may not be relevant where access to anti-retroviral drugs are limited, but provides a powerful indication of how effective these treatments are where they are available.
Forty percent of people living with HIV smoke, and 20 percent are ex-smokers. This is in stark contrast to the general population, where anti-smoking campaigns have brought the rate of adult smoking down to 15 percent from over 40 percent in the 1960s.
Dr Krishna Reddy of Massachusetts General Hospital has published a study on the interactions of smoking and HIV in the Journal of Infectious Diseases. Her conclusion is clear: "A person with HIV who consistently takes anti-HIV medicines but smokes is much more likely to die of a smoking-related disease than of HIV," Reddy said in a statement.
For a person on anti-retroviral drugs, smoking reduces their life expectancy by more than eight years, Reddy found. Back when HIV was usually lethal within a few years that was a minor consideration. Today, however, Reddy's findings demonstrate that reducing smoking rates could achieve more than better management of the disease.
Quitting smoking does not entirely fix the problem, but it does undo a lot of the damage. HIV-positive men who quit at 40, for example, can expect to live only a year less than their counterparts who never smoked. “It's never too late to quit,” Reddy said.
Americans with HIV are known to be much less likely to stick to treatment plans than their European equivalents, reflecting differences in the medical systems. Reddy found that a 40-year-old individual taking anti-HIV drugs, but failing to follow their treatment plan perfectly, loses an average of six years compared to those who stick to their doctor's instructions. Damaging as this is, it is still less than the effect of smoking.
"It is time to recognize that smoking is now the primary killer of people with HIV who are receiving treatment," Dr Rochelle Walensky, the paper's senior author, said. Yet interventions against smoking have played a small part in the management of HIV.
A study like this cannot ethically be done through controlled trials. Instead, Reddy used the extensive epidemiological data available. This leaves open the possibility of confounding factors – for example whether smokers are also prone to other risky behaviors. However, the dangers of smoking are so well established, it is likely that tobacco itself represents most of the problem.